AB1360 DISTRIBUTION OF INFLAMMATORY/DEGENERATIVE/AMBIGUOUS LESIONS ON CONVENTIONAL LUMBAR LATERAL RADIOGRAPHS IN PSORIATIC ARTHRITIS PATIENTS
Authors: G. Ayan, A. Sadic, L. Kiliç, U. Kalyoncu
Journal: Annals of the Rheumatic Diseases (2022)

Background Psoriatic arthritis (PsA) patients are relatively older than spondyloarthritis patients, and accordingly, degenerative changes on spine are more frequent and confusing. Objectives The aim of this study is to determine the distribution, relation of different type of lesions on the lumbar spine in PsA patients receiving bDMARD therapy. Methods 182/274 (66.4%) patients had lateral lumbar radiographs. Two and three lumbar radiographs were present in 53 (19.3%) 14 (5.1%) patients respectively. The upper and lower regions of each vertebra were evaluated between T12, S1 (total of 2184 regions). Lesions were determined as osteophyte (O) (grade 0-3), vertebral corner erosion, sclerosis, squaring, corner syndesmophyte (SP), bridging SP. While osteophyte was determined according to the degenerative character of new bone formations, the definition of SP was made according to mSSASS. Lesions that the clear distinction of cannot be made were defined as ambigious. For patients with follow-up radiographs, the change of lesions defined as ambigious was also recorded. All of the assessments were done by an experienced rheumatologis (UK) and in cases with suspicion, another experienced rheumatologist reviewed the cases (LK) and a consensus was reached. Results The mean (SD) age of 182 PsA (69.2% female) patients was 47.6 (12.7), the age at diagnosis of PsA was 39.7 (12.7). Of the patients, 112 (61.5%) met the criteria for mNY. There was at least one abnormality in 111 (61.0%) patients with lumbar spine radiograph. O was the most frequently detected lesions (42.3%), with 18.1% of patients having O grade 2 and above. While SP was present in 24.2% of all patients, ambigious lesions were detected in 13 (4.7%) patients. While O were most frequently grouped between L2 upper and L4 upper regions, SPs were distributed in a similar ratio between L4 upper and T12 lower regions. Ambigious lesions were anywhere between T12 sub-L5. Patients with ambigious lesions were older (55.7 (9.8) vs 47.0 (12.7), p=0.017), lumbar mSSASS score was higher (5.4 (8.1) vs 1.6 (3.8), p=0.002) corner SPs (46.1% vs. %) 17.7, p=0.013) and bridging SPs (30.7% vs 7.7%, p=0.006) were more common, while no difference was found in terms of O grade 2 (23.1% vs 17.7%, p=0.63). Changes were observed in 5 ambigious lesions in patients with follow-up lumbar radiography, 4 of them transformed into corner SP at follow-up, and one was evaluated as osteophyte grade 2. Conclusion Approximately one-fifth of patients presenting with significant degenerative new bone formation and SP was found in one fourth. In approximately 5% of all patients, lesions in the lumbar vertebrae could not be differentiated. The frequency of SPs in other vertebral areas are more prominent in patients with ambigious lesions. It is seen that ambigious lesions turn into SPs in a small group of patients with follow-up data. The nature of these lesions needs to be evaluated in further imaging studies. Table 1. The distribution of the lesions on lumbar spine Location Osteophyte Osteophyte ≥ 2 Corner SP Bridging SP All SP Erosion, Ambigious Sclerosis, Squaring T12 L, n (%) 7 (3.8) 1 (0.5) 9 (4.9) 5 (2.7) 14 (7.7) 3 (1.6) 2 (1.1) L1, U n (%) 6 (3.3) 0 (0) 10 (5.5) 5 (2.7) 15 (8.2) 2 (1.1) 2 (1.1) L1, L, n (%) 10 (5.5) 6 (3.3) 8 (4.4) 6 (3.3) 14 (7.7) 4 (2.2) 0 (0) L2, U, n (%) 15 (8.2) 8 (4.4) 8 (4.4) 7 (3.8) 15 (8.2) 4 (2.2) 4 (2.2) L2, L n (%) 16 (8.8) 6 (3.3) 5 (2.7) 6 (3.3) 11 (6.0) 4 (2.2) 0 (0) L3,U n (%) 31 (17.0) 13 (7.1) 4 (2.2) 6 (3.3) 10 (5.5) 10 (5.5) 2 (1.1) L3,L n (%) 17 (9.3) 8 (4.4) 3 (1.6) 5 (2.7) 8 (4.4) 5 (2.7) 2 (1.1) L4,U, n (%) 37 (20.3) 14 (7.7) 8 (4.4) 5 (2.1) 13 (7.1) 11 (6.0) 4 (2.2) L4, L n (%) 10 (5.5) 1 (0.5) 3 (1.6) 1 (0.5) 4 (2.2) 6 (3.3) 4 (2.2) L5, U n (%) 24 (13.2) 8 (4.4) 1 (0.5) 1 (0.5) 2 (1.1) 1 (0.5) 1 (0.5) L5,L n (%) 8 (4.4) 3 (1.6) 1 (0.5) 1 (0.5) 2 (1.1) 0 (0) 0 (0) S1, U, n (%) 3 (1.6) 3 (1.6) 0 (0) 1 (0.5) 1 (0.5) 0 (0) 0 (0) All vertebral corners (n=2184) 184 (8.4) 75 (3.4) 60 (2.7) 49 (2.2) 109 (4.9) 50 (2.2) 21 (1.0) All patients 77 (42.3) 33 (18.1) 36 (19.8) 17 (9.3) 44 (24.2) 22 (12.1) 13 (4.7) SP:Syndesmophyte, L:Lower, U:Upper Disclosure of Interests None declared